Is 10% cashback actually good? How to tell in ten seconds

Someone quotes you "10% cashback" and it sounds great. But 10% at a store that normally pays 12% is a bad day to buy, and 4% at a store that usually crawls along at 1% is a genuine steal. The headline number, on its own, tells you almost nothing. What tells you something is the verdict.

That's the whole idea behind this site: a rate is only "good" relative to itself (e.g. compared to the store's rate history).

The ten-second test

Before you buy, ask two questions:

1. What's the best rate available across all portals right now? Not just the first portal you thought of, the best one.
2. How does that rate compare to what this store usually pays?

Here's what that looks like for Nike across every portal we track:

The top of that table answers question one. CBYS does the math for you on question #2: we compare today's rate against that store's history, weighted by how long each rate actually held.

That verdict is the ten-second answer, and a chip beside most rates tells you that answer. "Above usual" means today is a good day to buy. "Below usual" means today's rate is below what that store typically pays on that portal (hover over the chip and it'll tell you the usual range). "Highest yet" means don't overthink it: go. This means the rate is the best we've tracked for that store on that portal and/or the best rate over the past year.

Why a big number can be a trap

Two things can make a rate look bigger than it is, without actually making it a better deal:

• "Up to" rates. "Up to 10% back" often means 10% on one narrow category and 2% on everything else. We badge those, so you can tell a theoretical ceiling from a rate you'll actually earn (the glossary has the full story on "up to").
• A number with no history behind it. Portals frequently raise and lower rates. A high rate - without context - doesn't tell you that the rate is necessarily good or bad. However, couple a rate with the data CBYS has collected about that portal and store, and you can make an informed decision based on historical data.

Here's what that movement looks like: one store, two portals, since we started tracking it.

Where to see it for yourself

Every store page on this site runs this comparison for you. And if you just want to see what's unusually high right now, across every store, that's the rate highs page. Here's what's on it at the moment:

Next time a deal blog shouts a big cashback number at you, run the ten-second test: find the best rate across portals, then check it against that store's own history. The verdict handles that second half for you - so: check before you shop.

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